Smbclient Symlink to the router root files system


I have a USB device connected to the router, I shared the content of the files using samba, I want to create a symbolic link from the USB device to the root folder of the router.
what are the steps to do that, there is a command smb: > symlink <link_target>
what's the param link_target to get the root folder?
we need to prepare a shared folder in the router first, or it's possible to do that directly using smbclient session?